Photoemission Spectroscopy Technique - Basic Principles and Some Uses 

by Prof. Elena María Echeverría Mora

Abstract: The photoelectric effect discovered by Heinrich Rudolf Hertz in 1887 and explained by Albert Einstein in 1905 is an important phenomenon that has a lot of applications nowadays. The PhotoElectron Spectroscopy (PES) is one of these applications. This is a powerful tool to characterize materials. Although it is a surface-sensitive technique, it is possible to obtain important structural information about the studied samples. Depending on the excitation energy used during the data collection, it is possible to get information on the bonding environment, elemental composition, or valence band of the system being investigated. In this talk, I will give a brief introduction to the photoelectric effect and its applications. Then, I will focus on PES and will show how this technique can be used. The talk aims to provide a general understanding of how this technique works, and how it can be used to gain important knowledge of the system of interest.

Recent Advances of Giant Magnetoimpedance (GMI)-based Sensors for Industrial and Bioengineering Applications 

by Prof. Ongard Thiabgoh

Abstract: Recently, the large change in the complex impedance of amorphous magnetic materials known as “the Giant Magneto-impedance (GMI) effect” has revealed a new class of ultrahigh sensitivity magnetic sensors with pico-Tesla resolution at room temperature. This GMI-based sensor is highly promising for active sensing and real-time monitoring building block for modern industrial devices and healthcare applications. We have investigated  surface morphology, microstructure, surface magnetic property, and magnetic domain structure of the magnetic microwires using techniques scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), magneto-optical Kerr effect (MOKE) magnetometry, and magnetic force microscopy (MFM). We demonstrated the high-frequency GMI response, its field sensitivity and circumferential domain structures of the melt-extracted magnetic microwires can be enhanced through the dc Joule annealing technique. A new class of high-frequency GMI-based sensor designed and fabricated using the optimal magnetic microwires shows higher field sensitivity than the commercially available Gaussmeters. The practical utility of the high sensitivity of the miniaturized sensor of weak magnetic fields can be applied for an autonomous support system and industrial applications.  A new sensor based on a magnetic coil, which is made of Co-rich melt-extracted microwire for the detection of small magnetic fields is highly promising for active respiratory motion monitoring, eye movement detection and other biomedical field sensing applications. 

The Rayleigh-Taylor Instability Near Midnight: Where do late night plasma plumes come from?

by Dr. Jonathon Smith

8:00 AM-10:00 AM

Abstract: Irregularities in the ionospheric plasma density can mangle GNSS signals. Near the equator they appear as large plumes of rising low density plasma in the ionosphere. The Rayleigh-Taylor instability can generate these plumes. Though seen mostly at dusk, their occurrence sometimes extends into post-midnight hours. This could be because they grow slowly at dusk, and drift to a later local time or they might grow at these later local times. By comparing the strength of the RT instability to bubble occurrence frequencies, we show that the ionosphere produces a conducive environment to create irregularities at later local times. Understanding the spatial and temporal distribution of the irregularities is important for mitigating the negative impact they can have on GNSS signals.

Gravitational Lensing and Hydrodynamic Simulation of Cluster Merger Abel 2146 

by Dr. Joseph E. Coleman

10:00 AM-12:00PM

Abstract: Abel 2146 is a cluster merger close to the plane of the sky.  This orientation allows for viewing the aftermath of the collision of two galaxy clusters.  Gravitational lensing allows mapping the dark mater in the system.  A dark matter core of one of the clusters lags behind a mass peak in the baryonic or visible matter. Simulations of the merger indicate complex relationship with collision angle with the X-ray signal.

Differential Ion Motion in Perovskite Light Emitting Electrochemical Cells

by Dr. Aditya Mishra

9:30 AM-12 Noon

Absract: Perovskite light emitting diodes (PeLED) have shown promising progress as next-generation efficient electroluminescent devices. However, PeLEDs suffer from low lifetimes and color instability during operation that limits its insertion into most practical applications. To address this concern, we investigated a form of perovskite light-emitting device termed perovskite light-emitting electrochemical cells (PeLECs) that utilize a phenomenon of selective differential ion motion in perovskite devices. We demonstrated that optimized Li salt additive improves thin film morphology, increases PL stability and quantum yield, reduces charge traps, and strengthens the perovskite chemical bonding. Leveraging differential ion motion in PeLECs demonstrates a new pathway of utilizing simple and smart, wearable devices for the internet of things (IoT) for digital communication and fashion.

Future of Portable Raman Spectrometers and SERS

by Dr. Hue Minh Nguyen

1:00PM-2:30PM

Abstract: In recent years, portable Raman spectrometers and commercialized surface-enhanced Raman scattering (SERS) substrates have become increasingly popular. They have turned out to be great tools for both substance detection, identification, and on-site analysis. SERS is one of the methods of resolving the bottleneck issue of Raman spectroscopy due to its inherent low signal level of the inelastic scattering of photons on molecules. The localized electromagnetic field at the hot spots on the SERS substrates helps to boost up the Raman signal many orders of magnitude. However, there is difficulty in collecting Raman spectra using SERS substrates caused of the distribution of the hot spots and/or investigated molecules at their proximity and photodegradation processes. We would like to discuss the design and construction of an affordable portable Raman spectrometer and the technique to collect proper Raman spectra using SERS substrates and portable Raman spectrometers. We propose a random sampling technique that gives representative and high-quality spectra with high intensity and good resolution. Potentially, this method can promote quantitative SERS and chemical trace analysis using portable Raman spectrometers.

In the spotlight in LiTalk this coming June 29, 2022, 9-11am, is Ms. Hillary Diane Andales, an Astrophysicist Undergrad Researcher from Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, United States. In this webinar, Ms. Andales will about their work on "Searching for the Remnants of the Oldest and Faintest Galaxies Accreted by the Milky Way".

The Liknayan Talks (LiTalk) is a monthly science/physics research colloquium organized by the Society of Physics Graduate Students (SPGS) and the Department of Physics of MSU-IIT, which serves as an avenue for the undergraduate and graduate students to share and/or learn the latest advances on their respective fields. This event is also co-hosted by the Department of Physics and the Society of Physics Graduate Students of MSU-Marawi; and the Caraga State University - Department of Physics. 

Zoom Meeting Link: https://us02web.zoom.us/j/81884993163...

Zoom Meeting ID: 818 8499 3163

Passcode: liknayan

For further details, please visit https://msuiit.edu.ph/events/details.php?id=617